使用SAX解析XML

1.概述

SAX（simple API for XML）是一种XML解析的替代方法。相比于DOM，SAX是一种速度更快，更有效的方法。

2.XML文件

在类路径下新建xml文件

boot.xml

<?xml version="1.0" encoding="UTF-8" ?>
<book id="1">
    <name>Java核心技术</name>
    <author>Cay S. Horstmann</author>
    <isbn lang="CN">1234567</isbn>
    <tags>
        <tag>Java</tag>
        <tag>Network</tag>
    </tags>
    <pubDate/>
</book>

3.使用SAX解析XML

    @Test
    public void test() throws Exception {
        InputStream input = SAXTest.class.getResourceAsStream("/book.xml");
        SAXParserFactory spf = SAXParserFactory.newInstance();
        SAXParser saxParser = spf.newSAXParser();
        saxParser.parse(input, new MyHandler());
    }

    class MyHandler extends DefaultHandler {

        @Override
        public void startDocument() throws SAXException {
            // System.out.println("start document");
        }

        @Override
        public void endDocument() throws SAXException {
            // System.out.println("end document");
        }

        @Override
        public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
            StringBuilder builder = new StringBuilder();
            builder.append("<");
            builder.append(qName);

            // 处理属性
            for (int i = 0; i < attributes.getLength(); ++i) {
                String attrName = attributes.getQName(i);
                String attrValue = attributes.getValue(i);
                builder.append(String.format(" %s='%s' ", attrName, attrValue));
            }
            builder.append(">");

            System.out.print(builder.toString());
        }

        @Override
        public void endElement(String uri, String localName, String qName) throws SAXException {
            System.out.print("</" + qName + ">");
        }

        @Override
        public void characters(char[] ch, int start, int length) throws SAXException {
            String str = new String(ch, start, length);
            System.out.print(str);
        }

        @Override
        public void error(SAXParseException e) throws SAXException {
            System.out.print("error:" + e);
        }
    }

4.结果